Synchronous electric motor with automatic starter



Nov. 2, 1948. o. SCHILD 2,452,958

SYNCHRONOUS ELECTRIC MOTOR WITH AUTOMATIC STARTER Filed Dec. 17, 1946 5,, o "n 1-4 F Q I INVENTOI? 07% 54/6/74? FrTTOl-TNE Y Patented Nov. 2, 1948 SYNCHRONOUS ELECTRIC MOTOR WITH AUTOMATIC STARTER Otto Schild, La Chaux-de-Fonds, Switzerland Application December 17, 1946, Serial No. 716,826 In Switzerland October 21, 1946 2 Claims.

The object of the present invention is a synchronous electric motor with automatic starter.

This starter is characterized by a stator magnetic circuit presenting an air. gap, by a movable armature cooperating with this air gap, by a gear meshing with a pinion-fixed at the shaft end of the rotor, and by a pawl linked with the movable armature and cooperating with said gear in such a way as to start the motor as soon as it is put under tension.

The attached drawing represents by way of example an embodiment of the invention.

Fig. 1 is an elevation view thereof.

Fig. 2 is a side-view.

In the embodiment shown, the .starter comprises a movable armature I mounted on a lever 2 pivoted in 3 so as to be aptto move and bridge an air gap 4 provided in the magnetic circuit 5 of the stator of the synchronous motor. The latter carries a field coil 6 and comprises two toothed poles l cooperating with a toothed rotor 8. The shaft of the rotor carr es a pinion 9 meshing with a first gear I0 of a clock work partially shown.

The pivot 3 carries a second lever ll linked with lever 2 by a spring l2 whose elongation is limited by a stop l3. At the end of lever H is mounted a pawl H pivoted in Hand cooperating with the teeth of gear Ill,

The operation of this starter is as follows:

When current is sent through the coil 6, the magnetic fiux draws the armature l and the lever 2 pulls lever ll through the action of spring l2 and stop l3. The gear l0 thus receives from pawl l4 an impulse without knock which gives the motor a speed which is sufficient for starting it.

When the current is accidentally cut out, the motor will be automatically re-started in the same way as soon as the current is re-established; this is a great advantage over the manual starters, considering the frequent short interruptions that occur on networks.

What I claim is:

1. In a synchronous electric motor with automatic starter, in particular for clockworks, a frame. a rotor mounted rotatively in said frame, a driving pinion centered on said rotor, a first driven gear mounted rotatively in said frame, in mesh with said pinion. two pole pieces of unequal lengths, secured on said frame in space relation with said rotor, a yoke bridging said pole pieces and secured thereon, a non-magnetic spacer inserted between said yoke and the shorter one of said pole pieces, in order to produce a gap across the entire section of the main magnetic flux path, a magnetic armature mounted pivotally on said shorter pole piece in such a way as to be apt to bridge said gap and thereby restore the entire section of the main magnetic flux path, and operative means of transmission of movement between said armature and said first driven gear.

2. In a synchronous electricmotor with automatic starter, in particular for clockworks, a frame, a rotor mounted rotatively in said frame, a driving pinion centered on said rotor, a first driven gear mounted rotatively in said frame, in mesh with said pinion, two pole pieces of unequal lengths secured on said frame in space relation with said rotor, a yoke bridging said pole pieces and secured thereon, a non-magnetic spacer inserted between said yoke and the shorter one of said pole pieces, in order to produce a gap across the entire section of the main magnetic flux path, a magnetic armature mounted pivotally on said shorter pole piece in such a way as to be apt to bridge said gap and thereby restore the entire section of the main magnetic fiux path, and operative means of transmission of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1 895,637 Meissner Jan. 31, 1933 2,027,944 Whitehead Jan. 14, 1936 

